1. Field of the Invention
The present invention relates to a recording tape cartridge accommodating, within a case, a single reel on which is wound a recording tape, such as a magnetic tape or the like, which is used as a recording/playback medium mainly of computers or the like.
2. Description of the Related Art
Conventionally, magnetic tape cartridges have been known in which a magnetic tape, which is used as a data recording/playback medium of a computer or the like, is wound on a single reel, and the reel is accommodated in a case. A leader member, such as a leader pin, a leader tape, or a leader block, is provided at the distal end of the magnetic tape. A pull-out means provided at a drive device pulls the leader member out from an opening of the magnetic tape cartridge, and winds the magnetic tape, which is fixed to the leader member, onto a take-up reel of the drive device.
A reel gear is formed in an annular form in the center of the bottom surface of a reel which emerges from an open hole formed in the bottom surface of the magnetic tape cartridge. Due to a driving gear, which is provided at a rotating shaft of the drive device, meshing with this reel gear, the reel is driven to rotate. By rotating the reel of the magnetic tape cartridge and the take-up reel of the drive device synchronously, data can be recorded onto the magnetic tape, and data recorded on the magnetic tape can be played back.
A large amount of data can be recorded in the magnetic tape cartridge. The case of the magnetic tape cartridge is formed in a substantially rectangular form in which peripheral walls of an upper case and a lower case, which are made of a synthetic resin, are joined together by welding, screws, or the like. Little space is required for storage of the magnetic tape cartridge. Further, as shown in FIG. 9, drafts for facilitating removal from molds for molding are formed at peripheral walls 66A, 68A of an upper case 66 and a lower case 68. This draft β is usually about 1° to 2° as seen in the side sectional view of FIG. 9. In this way, the upper case 66 and the lower case 68, which are molded products, can be smoothly removed from the molds for molding thereof.
Moreover, in such a magnetic tape cartridge, the position of the opening differs for each type of leader member. For example, in a case in which a leader pin is used, the opening is formed at a corner portion at the side of loading the magnetic tape cartridge into a drive device. A pair of upper and lower pin holding portions, which hold the leader pin in an upright state when the magnetic tape cartridge is not being used (is being stored or the like), are provided at the inner surface of the ceiling plate of the upper case and the inner surface of the floor plate of the lower case in a vicinity of the opening. The pin holding portions are formed in substantially semicylindrical shapes as seen in plan view, and respective one portions thereof are open so that the leader pin can enter therein and exit therefrom. As shown in FIG. 10A, both end portions 60A of the leader pin 60, which is in a state of standing upright, are inserted and held in pin holding portions 62.
However, when the case is dropped and a peripheral wall at which a draft is formed in this way, and in particular, the peripheral wall at the side of loading into a drive device at which peripheral wall the opening is formed at the end portion thereof (i.e., the front wall) hits the ground, if the vicinity of opening is joined together by screws, as shown in FIG. 10B, a front wall 64 (the peripheral walls 66A, 68A) in a vicinity of the opening may flexurally deform so as to be pushed toward the inner side of the case, due to the impact of the drop. Accompanying this flexural deformation, a ceiling plate 66B of the upper case 66 and a floor plate 68B of the lower case 68 flexurally deform toward the outer sides.
When such flexural deformation arises, because the both end portions 60A of the leader pin 60 are held in the pin holding portions 62 which are formed at the inner surface of the ceiling plate of the upper case 66 and the inner surface of the floor plate of the lower case 68, the both end portions 60A of the leader pin 60 may fall out from the pin holding portions 62, or the positions thereof may become offset. At the time when the magnetic tape cartridge is loaded into a drive device, the problem that a pull-out means provided at the drive device cannot pull the leader pin 60 out may arise.